2002 neon speedometer jumping and won't up-shift

It was raining and my check engine light went on. Then the speedometer started jumping and it wouldn't up-shift-I changed the input and output sensors and unhooked the battery for about 30 minutes. I started it up and the light was off. I drove about a block and it started doing samething. If I unhook the battery and rehook it up right away the light will stay off for about a block. sometimes it will still shift fine will the speedometer is jumping-

May be the connection at the output speed sensor, it supplies vehicle speed signal to Trans module. Same signal used for speedo. Have seen wires break right at the sensor. U may also want to check those codes especially in the TCM. See if it gives u an output speed sensor code or gear ratio code. If either of these are present, it's probably in the output not input sensor circuit. With a wiring diagram, u could ohm the wires to the TCM and wiggle wires and connector to check for an open.

The big wire bundle connecting the TCM (which is in the front wheelwell passenger side under the window washer bottle) to the solienoid pack (crescent shaped metal unit mounted on front of transaxel below the massive air cleaner) runs below the radiator, and as the lowest hanging thing on this low slung car is only 4 inches above the massive concrete grinding wheel (road) that it drives over day after day for the life of the car. this 2" diameter wire bundle has wires worn in two often where the bundle turns from its downward path from the solenoid pack to its horizontal path accross the bottom of the car to the TCM. the pink wire with black stripe comes from the TCM to pin 5 of the solenoid pack and should tell the pack to shift the transmission to high gear at the proper speed while accelerating. this wire was worn in two on my sons 2002 neon se with 41te transmission. Sometimes it was open disabling higest gear so tansmission would get up to 3rd gear and stay there as engine started to roar, and. other times it seemed to short before starting out telling the transmission to go directly to 4th gear, causing the transmission to strain too much and the TCM would shut solenoid pack down making it seem like there was no connection to the wheels at all, then the transmission would wrap up and **** ahead causing the speedometer needle to bounce. in this second condition the car would sit there often after a block or so with engine roaring and not only not move forward, but if on a slope, would roll backwards, while the engine was roaring. when wire was open 12v to pin 4 of solenoid pack was missing. this voltage Comes from pin 46 relay 28 on fuse panel aft of aircleaner. this 12v comes to the relay pin45 supplied from fuse 17, and is turned off and on by TCM which supplies 12v turn on signal to relay # 28 coil on pin48, with coil grounded on pin 44. as best I can reason it out, the TCM was turning the solienoid pack off disabling the transmission to protect it from being destroyed by roaring down the road at 40 mph when transmission couldnt shift to highest gear. repairing this pink wire with black stripe under the radiator fixed all these problems. No wireing diagram seems available for this circuit. I assume any of the 7 wires from the TCM to the solenoid pack could cause similar problems. I believe pins 5,6,7 and 8 are signals from TCM telling the transmission to shift through its 4 forward gears. I believe 1,2,and 3 may be sensor signals to TCM advising it of condition of shifting process. while pin4 both powers the solenoid pack and tlls the TCM the solenoid pack is powered. If I could find a wireing diagram for this circuit, I could be certain of some things I am guessing about, and would ohm out and replace any bad wires end to end. The pins on the solenoid pack have wire colors as follows: pin 1 yellow, pin 2 grey with salmon stripe, pin3 orange, pin 4 larger red (12v power) pin 5 pink with black stripe, pin 6 brown, pin7 baby blue, pin 8 white. all of these should go to/come from TCM, wwith 12v power pin4 also comming from fuse panel as noted above. I planned to repair this properly and insulate it well, but luck being what it was, i fixed it in the rain unable to insulate it well only heatshrinking that wire alone and when it worked, tieing up the bundle with spot tie, and it went band again 6 mo later. so if you find and fix this, do it well the first time.

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Related Questions:

Maybe the speedometer connection at the transmission might be interfering with the shift lever at the transmission. Not sure if this would apply to the 2002 Neon but on some older model cars I believe it could happen. Just a thought.

the vehicle speed sensor may have gone bad however usually this will set the check engine light on the dash and cause a shifting problem(early or late shift)while driving.the cruise won`t work.if this is not happening then the problem could be the speedometer head in the dash,or a poor connection for the speedometer where the instrument cluster fastens to the connector in the dash panel.some of these had problems with the power relay box under the hood on the drivers side,with corrosion on the underside of the box.

If trans is still shifting its most likely a blown cluster fuse or bad cluster.If you have a check engine light & trans don't shift most likely blown trans fuse or trans vss (speedo) harness at right drive axle broken puple with white stripe wire or light green wire with black stripe